A nurse is teaching a newly licensed nurse about didanosine therapy.
Which of the following client conditions should the nurse identify as an indication for treatment with didanosine?

Choice A rationale

Pseudoephedrine is a sympathomimetic agent that primarily acts as a vasoconstrictor and bronchodilator. It does not directly affect kidney function to cause polyuria. In fact, due to its vasoconstrictive properties, it could theoretically decrease renal blood flow, although this is not a common or expected adverse effect leading to increased urine output.

Choice B rationale

Pseudoephedrine's primary mechanism of action involves stimulating alpha- and beta-adrenergic receptors. It does not have a known effect on appetite regulation; it is not typically associated with either increased or decreased appetite. Therefore, an increased appetite is not an expected adverse effect of this medication.

Choice C rationale

Pseudoephedrine is a sympathomimetic drug that stimulates adrenergic receptors, leading to effects similar to sympathetic nervous system activation. This stimulation typically results in tachycardia, not bradycardia. It increases heart rate and contractility, which can be problematic for individuals with pre-existing cardiovascular conditions.

Choice D rationale

As a sympathomimetic, pseudoephedrine causes vasoconstriction by stimulating alpha-1 adrenergic receptors in the arterioles. This widespread vasoconstriction leads to an increase in peripheral vascular resistance, which in turn can elevate blood pressure. Therefore, hypertension is a common and important adverse effect to monitor for, especially in individuals with pre-existing hypertension.

Choice A rationale

Gastrointestinal reflux, or GERD, is a condition where stomach acid flows back into the esophagus. While triptans can sometimes cause mild gastrointestinal upset, GERD itself is not a contraindication to sumatriptan use. The mechanism of action of sumatriptan involves serotonin receptor agonism, which does not significantly exacerbate or directly interact with the pathophysiology of gastrointestinal reflux disease.

Choice B rationale

Angina pectoris is chest pain caused by reduced blood flow to the heart muscle, often due to coronary artery disease. Sumatriptan causes vasoconstriction by acting on serotonin 5-HT1B/1D receptors. This generalized vasoconstrictive effect can lead to coronary artery spasm and worsen myocardial ischemia, making it a significant contraindication in patients with cardiovascular conditions like angina pectoris or a history of myocardial infarction.

Choice C rationale

Routine acetylsalicylic acid (aspirin) use is common for its antiplatelet and analgesic properties. There is no known direct contraindication to sumatriptan use in patients taking routine acetylsalicylic acid. While both medications can affect platelet function, their mechanisms of action and indications are distinct, and concurrent use is generally considered safe if no other contraindications exist.

Choice D rationale

Eczema is an inflammatory skin condition characterized by dry, itchy patches. Eczema is a dermatological condition and does not have any physiological or pharmacological interaction with sumatriptan's mechanism of action, which primarily involves vasoconstriction in the cerebral vasculature and inhibition of trigeminal nerve activity. Therefore, eczema is not a contraindication to sumatriptan therapy.